Regression test portability: hostname

The --fqdn option to hostname is Linux only
This is resubmission of the same patch. I assume the regression test
is a test bug

BUG: 764655
Change-Id: I6437124186435f10d1ee6a847e2593554d633716
Signed-off-by: Emmanuel Dreyfus <manu@netbsd.org>
Reviewed-on: http://review.gluster.org/8282
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Harshavardhana <harsha@harshavardhana.net>
Tested-by: Harshavardhana <harsha@harshavardhana.net>